The quantum entanglement is considered as one of the most important notions of quantum computing. The entanglement is a feature of quantum systems and it is used as a basis for many quantum algorithms and protocols. In this presentation we analyze the level of entanglement for the quantum switch, during its work. The level of entanglement during the correct operating may be compared with the situation when a noise is present in the analyzed system. The noise changes the level of quantum entanglement and we utilize this observation to evaluate if the switch works properly.

We present a link between the combinatorial notion of orthogonal arrays and k-uniform states, i.e., multipartite pure states such that every reduction to k parties is maximally mixed. As consequence, simple constructions of 1 and 2 uniform states for homogeneous (N qudits) and heterogeneous systems (e.g. N qubits + M qutrits) are derived.

Classical methods for processing and analysis of multidimensional signals – such as color videos and hyperspectral images – do not exploit full information contained in inner their factors. On the other hand, recently developed tensor based methods allow for data representation and analysis which directly account for data multidimensionality. Examples can be found in many applications such as face recognition, image synthesis, video analysis, surveillance systems, sensor networks, data stream analysis, marketing and medical data analysis, to name a few.